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Lead transport properties of carboxylic acid and synthetic ionophores

Hamidinia, Shawn A
http://rave.ohiolink.edu/etdc/view?acc_num=osu1119907268

Abstract Details

2005, Doctor of Philosophy, Ohio State University, Biophysics.
Metal ion transport studies were performed using naturally occurring carboxylic acid ionophores, a synthetic ionophore, and phospholipid vesicles. Several compounds were identified that are highly selective for the transport of Pb2+ compared to physiological monovalent and divalent cations. Based upon their respective second-order rate constants, the compounds nigericin and monensin were shown to be selective for the transport of Pb2+, with nigericin being slightly more selective in that regard. Plots of log rate vs. log Pb2+ or log ionophore concentration, in addition to pH dependency, indicate that the predominant transporting species are NigPbOH or MonPbOH. Agents that collapse membrane potential were not required to achieve a high transport rate, which is indicative of an electroneutral mechanism. Nigericin and monensin catalyzed transport of Pb2+ are only modestly affected by physiological concentrations of Ca2+, Mg2+, Na+, or K+. These findings led to the testing of monensin as a therapeutic agent for Pb intoxication using an intact rat model. Monensin at a concentration of 100 ppm in the feed was given to rats exposed to 100 ppm Pb(acetate)2 in drinking water over a three week period. A reduced Pb accumulation in several organs and tissues was shown. Furthermore, there was an acceleration in the excretion of Pb without depleting organs of essential trace metals such as Zn2+ and Cu2+. An additional study showed that the co-administration of 100 ppm monensin with meso-dimercaptosuccinate after an exposure to 100 ppm Pb(acetate)2 in drinking water for three weeks significantly reduced the Pb content from femur, brain, and heart without markedly perturbing the concentrations of physiological elements. Thus, monensin may be useful for the treatment of Pb poisoning when combined with DMSA. KTC-15-cr-5 was synthesized and found to be an effective ionophore for Pb2+ and Cd2+ transport across a phospholipid bilayer. The results suggest that Pb2+ and Cd2+ are primarily transported as a 1:1 complex and by an electrogenic mechanism. The high selectivity for Pb and Cd is of possible value for Pb/Cd intoxication and furthermore to wastewater treatment.
Douglas Pfeiffer (Advisor)
157 p.
Biophysics, Medical
monensin; Pb2; IONOPHORES; DMSA; Pb; Erdahl

Recommended Citations

Citations

  • Hamidinia, S. A. (2005). Lead transport properties of carboxylic acid and synthetic ionophores [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1119907268

    APA Style (7th edition)

  • Hamidinia, Shawn. Lead transport properties of carboxylic acid and synthetic ionophores. 2005. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1119907268.

    MLA Style (8th edition)

  • Hamidinia, Shawn. "Lead transport properties of carboxylic acid and synthetic ionophores." Doctoral dissertation, Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1119907268

    Chicago Manual of Style (17th edition)

osu1119907268
1,545
© 2005, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.