ISSN:
1573-0972
Keywords:
Chemical nature
;
compartmentalization
;
copper uptake
;
Pseudomonas aeruginosa
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract Copper-sensitive (Cus) and copper-resistant (Cur) strains of Pseudomonas aeruginosa were characterized in terms of Cu2+ sensitivity, uptake and its compartmentalization in the possible cell sectors. Minimum inhibitory concentrations (MICs) of Cu2+ for the Cur strain (3.2 mM and 0.12 mM in enriched- and in minimal-medium, respectively) were almost 5-fold higher over that of its sensitive counterpart. While Cus strain accumulated Cu2+ to a maximum of 1.8 μ mol mg−1 protein, Cur strain increased it to 2.37 μmol mg−1 protein. Both the strains also demonstrated energy- and pH-dependent Cu2+ uptake through the broad-substrate range divalent cation (Zn2+, Mg2+, Co2+) uptake system as well as through the system specific for Cu2+. Cell-fractionation study revealed that in Cur strain, periplasm and membrane are the main Cu2+ binding sites, whereas, in case of Cus strain, it is the cytoplasm. The overall observations indicate that the Cur strain restricted Cu2+ sequestration exterior to the cytoplasm as the possible strategy for Cu-resistance. The chemical nature of Cu2+ deposition in the respective strains was also ascertained by X-ray powder diffraction analysis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008997718811
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