Naphthalene uptake by a Pseudomonas fluorescens isolate

Document Type

Article

Publication Date

1-1-1998

Abstract

The uptake of naphthalene has been investigated in the metabolizing cells of Pseudomonas fluorescens utilizing [1-14C]naphthalene. The uptake displayed an affinity constant (K(t)) of 11 μM and a maximal velocity (V(max)) of 17 nmol · h-1 · mg-1 cellular dry weight. Naphthalene uptake was not observed in a mutant strain, TG-5, which was unable to utilize naphthalene as a sole source of carbon for growth. Uptake was significantly inhibited (~90%) by the presence of growth-inhibiting levels of either azide or 2,4-dinitrophenol and was sensitive to the presence of structural analogues of naphthalene. The intracellular levels of ATP were not significantly reduced by the presence of either azide or 2,4-dinitrophenol and was sensitive to the presence of structural analogues of naphthalene. The intracellular levels of ATP were not significantly reduced by the presence of either azide or 2,4-dinitrophenol. The presence of α-naphthol was found to noncompetitively inhibit naphthalene uptake, displaying a K(i) of 0.041 μM. It is concluded that the first step in the utilization of naphthalene by Pseudomonas fluorescens is its transport into the cell by a specific energy- linked transport system.

Publication Title

Canadian Journal of Microbiology

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