BioSample

Protocols: Xenopus (X. tropicalis) females were purchased from the Xenopus national husbandry (CRB Xenopes), University of Rennes 1 (http://xenopus.univ-rennes1.fr/). The frogs were fed daily ad libitum with pellets of trout food. They were allowed to acclimatize for 3 weeks at 25ﾰC with a photoperiod of 12h:12h in constantly filtered water prior to starting the experiments Xenopus were exposed individually at 25ﾰC in 1 L glass jars protected from the light (3 individual replicates by times and exposure conditions). The exposure solutions consisted of 500 mL tap water (pH 7.8, organic carbon = 0.6 mg L-1, dissolved oxygen = 9.9 mg L-1, nitrate = 2.9 mg L-1, nitrites < 0.02 mg L-1) containing BaP at an initial concentration of 10 ﾵg L-1. Control frogs were exposed to ethanol (vehicle) at 1/1000 (v:v) concentration. To avoid circadian effects, experiments with control and BaP-exposed animals were conducted in parallel. The frogs were not fed during the exposure period (from 0 to 24h) For each biological replicate, total RNA was extracted from 15 mg liver using the RNAqueousﾮ-4PCR Kit (Ambion, USA) according to manufacturer's instructions. Total RNA quality and quantity were controlled on an Agilent 2100 Bioanalyzer (Agilent, USA). After extraction, total RNA from each biological replicate were equally pooled in order to obtain 8ﾵg of total RNA in 50ﾵl for each treatment and used for mRNAseq banks preparations using mRNA-Seq-8 Sample Prep Kit (Illumina, USA) according to manufacturer's instructions.