title: Development of a freeze-drying protocol for the long-term storage of S9-fraction at ambient temperatures.
abstract: The purpose of this study was to investigate the long-term stabilization of the liver S9-fraction that is widely used in genotoxicity assays in order to mimic bio-activating processes of xenobiotics in vitro. A successful long-term stabilization of the S9-fraction meets the growing demand for the construction of a lab independent device for the detection of genotoxic compounds in field studies with an integrated module for the metabolic activation of pre-genotoxic compounds. The carbohydrates sucrose, trehalose and raffinose were tested in different concentrations or mixtures in order to increase the product stability of the S9-fraction during and after freeze-drying. The activity of the freeze-dried S9-samples was evaluated by means of their potential to activate pre-genotoxic compounds. The successful long-term stabilization of enzymes of the rodent liver S9-fraction for 6 weeks at room temperature by freeze-drying in the presence of 250 mM trehalose is presented.
authors.affiliation: Department of Ecotoxicology and Biochemistry, Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz, Germany. buchinger@bafg.de
authors.forename: Sebastian
authors.initials: S
authors.lastname: Buchinger
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Campen
authors.forename: Eckard
authors.initials: E
authors.lastname: Helmers
authors.forename: Valeri
authors.initials: V
authors.lastname: Morosow
authors.forename: Marianne
authors.initials: M
authors.lastname: Krefft
authors.forename: Georg
authors.initials: G
authors.lastname: Reifferscheid
mesh_terms: D000818:Animals; D002243:Carbolines / Q000378:metabolism; D003451:Cryoprotective Agents / Q000494:pharmacology*; D005612:Freeze Drying / Q000379:methods*; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D011804:Quinolines / Q000378:metabolism; D011887:Raffinose / Q000494:pharmacology; D012377:Rodentia; D013395:Sucrose / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D014199:Trehalose / Q000494:pharmacology
chemical_list: D002243:Carbolines; D003451:Cryoprotective Agents; D011804:Quinolines; C029216:2-amino-3-methylimidazo(4,5-f)quinoline; D013395:Sucrose; D014199:Trehalose; C019132:3-amino-1,4-dimethyl-5H-pyrido(4,3-b)indole; D011887:Raffinose