title: Aluminum detoxication mechanism in Pseudomonas fluorescens is dependent on iron.
abstract: The soil microbe Pseudomonas fluorescens has been shown to detoxify aluminum by the elaboration of a soluble metabolite where the trivalent metal is sequestered [Appanna and St. Pierre, FEMS Microbiol. Lett. 24 (1994) 327-332]. The inclusion of 5 mM iron in the growth medium elicited an entirely disparate detoxification strategy. In this instance, the two trivalent metals were immobilized in a gelatinous lipid-rich residue. Dialysis and ultracentrifugation studies indicated that the test metals were being transformed from early stages of growth and were associated with phosphatidylethanolamine. However, at 45 h of cellular multiplication, most of the metals were deposited as an insoluble residue. X-ray fluorescence analyses identified the constituents of this mineral essentially as aluminum, iron and phosphorus. Scanning electron microscopy and energy dispersive X-ray microanalysis of the dialysate, isolated at 35 h of microbial growth, revealed thread-like structures associated with nodule-like bodies that were rich in the two test metals. Transmission electron microscopic studies aided in the visualization of iron and aluminum inclusions within the bacterial cells.
authors.affiliation: Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ont., Canada.
authors.forename: V D
authors.initials: VD
authors.lastname: Appanna
authors.forename: R
authors.initials: R
authors.lastname: Hamel
mesh_terms: D000535:Aluminum / Q000493:pharmacokinetics* / Q000633:toxicity*; D001673:Biodegradation, Environmental; D019343:Citric Acid / Q000378:metabolism; D004577:Electron Probe Microanalysis; D004785:Environmental Pollutants / Q000493:pharmacokinetics* / Q000633:toxicity*; D008658:Inactivation, Metabolic; D002479:Inclusion Bodies / Q000378:metabolism / Q000648:ultrastructure; D007501:Iron / Q000378:metabolism*; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D010714:Phosphatidylethanolamines / Q000378:metabolism; D011551:Pseudomonas fluorescens / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D012995:Solubility
chemical_list: D004785:Environmental Pollutants; D010714:Phosphatidylethanolamines; D019343:Citric Acid; D000535:Aluminum; D007501:Iron