324 TRANS URANIC ELEMENTS IN THE ENVIRONMENT 



TLC 



EXOCELLULAR 

 SOLUBLE 



Pu-DTPA 

 CONTROL 



INTRACELLULAR 

 SOLUBLE 



EXOCELLULAR 

 SOLUBLE 



Fig. 8 Thin-layer chromatographic (TLC) behavior in three solvent systems of plutonium 

 complexes separated by gel permeation chromatography. 



degrade or modify the DTPA moiety, allowing plutonium transfer to ligands arising from 

 microbial synthesis and degradation. 



The number of known compounds with the potential to bind plutonium more 

 strongly than DTPA appears to be quite limited, although hydroxamate derivatives 

 (Emergy, 1974), catechol derivatives (Tait, 1975), and tetrapyrrole ring systems (Balker, 

 1969) may exhibit this property. If modification of the Pu-DTPA occurred prior to 

 hgand transfer, then a myriad of microbially produced compounds, e.g., phenolic acids, 

 peptides, and carboxylic acids, has potential for binding plutonium (see previous 







TLE, 20 min 



© 



Fig. 9 Thin-layer electrophoretic (TLE) behavior of plutonium separated by gel 

 permeation chromatography. 



