TY - JOUR
T1 - Production of a molybdophore during metal-targeted dissolution of silicates by soil bacteria
AU - Liermann, Laura J.
AU - Guynn, Robin L.
AU - Anbar, Ariel
AU - Brantley, Susan L.
N1 - Funding Information:
The authors wish to thank Vanessa LeBron, summer BRIE undergraduate student, for help with initial experiments; Heather Buss and Rosemary Walsh for TEM sample preparation and imaging; William Page for providing strains OP, P100, and F196, and for helpful suggestions; Anne Duhme-Klair for providing purified azotochelin and aminochelin, and technical advice; and Jane Barling for conducting Mo isotope measurements. This work was funded by National Science Foundation (NSF) grant EAR 00-03565, Department of Energy (DOE) grant DE-FG02-01ER15209, the NASA Astrobiology Institute Cooperative Agreement NCC2-1057, and the Penn State Biogeochemical Research Initiative for Education (BRIE) sponsored by NSF grant DGE-9972759. [LW]
PY - 2005/8/5
Y1 - 2005/8/5
N2 - Although many bioessential metals are scarce in natural water and rock systems, microbial secretion of high-affinity ligands for metal extraction from solid phases has only been documented for Fe. However, we have discovered that Mo is extracted from a silicate by a high-affinity ligand (a possible "molybdophore") secreted by an N2-fixing soil bacterium. The putative molybdophore, aminochelin, is secreted as a siderophore under Fe-depleted conditions, but is also secreted under Fe-sufficient, Mo-depleted conditions. Presumably, molybdophore production facilitates uptake of Mo for use in Mo enzymes. In contrast, an Fe-requiring soil bacterium without a special Mo requirement only enhances the release of Fe from the silicate. Fractionation of Mo stable isotopes during uptake to cells may provide a "fingerprint" for the importance of chelating ligands in such systems. Many such metal-specific ligands secreted by prokaryotes for extraction of bioessential metals, their effects on Earth materials, and their possible utility in the recovery of economic metals remain to be discovered.
AB - Although many bioessential metals are scarce in natural water and rock systems, microbial secretion of high-affinity ligands for metal extraction from solid phases has only been documented for Fe. However, we have discovered that Mo is extracted from a silicate by a high-affinity ligand (a possible "molybdophore") secreted by an N2-fixing soil bacterium. The putative molybdophore, aminochelin, is secreted as a siderophore under Fe-depleted conditions, but is also secreted under Fe-sufficient, Mo-depleted conditions. Presumably, molybdophore production facilitates uptake of Mo for use in Mo enzymes. In contrast, an Fe-requiring soil bacterium without a special Mo requirement only enhances the release of Fe from the silicate. Fractionation of Mo stable isotopes during uptake to cells may provide a "fingerprint" for the importance of chelating ligands in such systems. Many such metal-specific ligands secreted by prokaryotes for extraction of bioessential metals, their effects on Earth materials, and their possible utility in the recovery of economic metals remain to be discovered.
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U2 - 10.1016/j.chemgeo.2005.04.013
DO - 10.1016/j.chemgeo.2005.04.013
M3 - Article
AN - SCOPUS:21844441881
VL - 220
SP - 285
EP - 302
JO - Chemical Geology
JF - Chemical Geology
SN - 0009-2541
IS - 3-4
ER -