title: Uptake of oxytetracycline and its phytotoxicity to alfalfa (Medicago sativa L.).
abstract: A series of experiments were conducted in a hydroponic system to investigate the uptake of oxytetracycline (OTC) and its toxicity to alfalfa (Medicago sativa L.). OTC inhibited alfalfa shoot and root growth by up to 61% and 85%, respectively. The kinetics of OTC uptake could be well described by Michaelis-Menten equation with Vmax of 2.25 micromol g-1 fresh weight h-1, and Km of 0.036 mM. The uptake of OTC by alfalfa was strongly inhibited by the metabolic inhibitor, 2,4-DNP (2,4-dinitrophenol), at pH 3.5 and 6.0, but not by the aquaporin competitors, glycerol and Ag+. OTC uptake, however, was significantly inhibited by Hg2+, suggesting that the inhibition of influx was due to general cellular stress rather than the specific action of Hg2+ on aquaporins. Results from the present study suggested that OTC uptake into alfalfa is an energy-dependent process.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: W D
authors.initials: WD
authors.lastname: Kong
authors.forename: Y G
authors.initials: YG
authors.lastname: Zhu
authors.forename: Y C
authors.initials: YC
authors.lastname: Liang
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: F A
authors.initials: FA
authors.lastname: Smith
authors.forename: M
authors.initials: M
authors.lastname: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000633:toxicity*; D004463:Ecology / Q000379:methods; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity*; D018527:Hydroponics; D000455:Medicago sativa / Q000187:drug effects / Q000378:metabolism*; D010118:Oxytetracycline / Q000493:pharmacokinetics / Q000633:toxicity*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development; D019155:Veterinary Drugs / Q000378:metabolism / Q000633:toxicity*
chemical_list: D000900:Anti-Bacterial Agents; D004785:Environmental Pollutants; D019155:Veterinary Drugs; D010118:Oxytetracycline