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Updated: Sep 23, 2026

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria
Published on: September 16, 2013
Laser spectroscopic studies of interactions of UVI with bacterial phosphate species
Roger Knopp1, Petra J Panak, Lewis A Wray
1Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA 94720, USA.
Abstract:
We have investigated the interactions of UVI with two bacterial phosphate-containing species: Gram-positive Bacillus sphaericus and Gram-negative Pseudomonas aeruginosa. The Gram-positive B. sphaericus was investigated by using Raman spectroscopy and time-resolved laser-induced fluorescence spectroscopy (TRLFS). We found that living cells, spores, and intact heat-killed cells complexed UVI (pH 4.5) through phosphate groups bound to their surfaces, while decomposed cells released H2PO4- and precipitated UVI as UO2(H2PO4)2. TRLFS of UVI showed that Gram-negative P. aeruginosa--genetically engineered to accumulate polyphosphate, subsequently degrade it, and secrete phosphate--precipitated UVI quantitatively at pH 4.5. The same bacterial strain, not induced to secrete phosphate, sorbed only a small amount of UVI.
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