Naphthalene uptake by a Pseudomonas fluorescens isolate.
The uptake of naphthalene has been investigated in the metabolizing cells of Pseudomonas fluorescens utilizing [1-14C]naphthalene. The uptake displayed an affinity constant (Kt) of 11 microM and a maximal velocity (Vmax) 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 (approximately 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. The presence of alpha-naphthol was found to noncompetitively inhibit naphthalene uptake, displaying a Ki of 0.041 microM. 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.
Department of GeoEnvironmental Science and Engineering, Wilkes University, Wilkes-Barre, PA 18766, USA.
B E
BE
Whitman
D R
DR
Lueking
J R
JR
Mihelcic
D019297:2,4-Dinitrophenol / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D001673:Biodegradation, Environmental / Q000187:drug effects; D001693:Biological Transport, Active; D009281:Naphthalenes / Q000378:metabolism*; D009284:Naphthols / Q000494:pharmacology; D011551:Pseudomonas fluorescens / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D019810:Sodium Azide / Q000494:pharmacology; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism; D013997:Time Factors
D009281:Naphthalenes; D009284:Naphthols; D012989:Soil Pollutants; C029350:1-naphthol; D000255:Adenosine Triphosphate; D019810:Sodium Azide; D019297:2,4-Dinitrophenol