title: Trans-membrane transport of n-octadecane by Pseudomonas sp. DG17.
abstract: The trans-membrane transport of hydrocarbons is an important and complex aspect of the process of biodegradation of hydrocarbons by microorganisms. The mechanism of transport of (14)C n-octadecane by Pseudomonas sp. DG17, an alkane-degrading bacterium, was studied by the addition of ATP inhibitors and different substrate concentrations. When the concentration of n-octadecane was higher than 4.54 μmol/L, the transport of (14)C n-octadecane was driven by a facilitated passive mechanism following the intra/extra substrate concentration gradient. However, when the cells were grown with a low concentration of the substrate, the cellular accumulation of n-octadecane, an energy-dependent process, was dramatically decreased by the presence of ATP inhibitors, and n-octadecane accumulation continually increased against its concentration gradient. Furthermore, the presence of non-labeled alkanes blocked (14)C n-octadecane transport only in the induced cells, and the trans-membrane transport of n-octadecane was specific with an apparent dissociation constant K t of 11.27 μmol/L and V max of 0.96 μmol/min/mg protein. The results indicated that the trans-membrane transport of n-octadecane by Pseudomonas sp. DG17 was related to the substrate concentration and ATP.
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing, 100875, P. R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Hua
authors.forename: Hong Qi
authors.initials: HQ
authors.lastname: Wang
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Yi Cun
authors.initials: YC
authors.lastname: Zhao
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000473:Alkanes / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001692:Biological Transport; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D006838:Hydrocarbons / Q000378:metabolism; D007700:Kinetics; D011549:Pseudomonas / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000473:Alkanes; D006838:Hydrocarbons; D000255:Adenosine Triphosphate; C022883:octadecane