Selection of reference genes for normalization of real-time PCR data in minipig heart failure model and evaluation of TNF-alpha mRNA expression
JOURNAL OF BIOTECHNOLOGY
Authors: Martino, Alessandro; Cabiati, Manuela; Campan, Manuela; Prescimone, Tommaso; Minocci, Daiana; Caselli, Chiara; Rossi, Anna Maria; Giannessi, Daniela; Del Ry, Silvia
Abstract
Real-time PCR is the benchmark method for measuring mRNA expression levels, but the accuracy and reproducibility of its data greatly depend on appropriate normalization strategies. Though the minipig model is largely used to study cardiovascular disease, no specific reference genes have been identified in porcine myocardium. The aim of the study was to identify and validate reference gene to be used in RTPCR studies of failing (HF) and non-failing pig hearts. Eight candidate reference genes (GAPDH, ACTB, B2M, TBP, HPRT-1, PPIA, TOP2B, YWHAZ) were selected to compare cardiac tissue of normal (n = 4) and HF (n= 5) minipigs. The most stable genes resulted: HPRT-1, TBP, PPIA (right and left atrium); PPIA, GAPDH, ACTB (right ventricle); HPRT-1, TBP, GAPDH (left ventricle). The normalization strategy was tested analyzing mRNA expression of TNF-alpha, which is known to be up-regulated in HF and whose variations resulted more significant when normalized with the appropriately selected reference genes. The findings obtained in this study underline the importance to provide a set of reference genes to normalize mRNA expression in HF and control minipigs. The use of unvalidated reference genes can generate biased results because also their expression could be altered by the experimental conditions. (C) 2011 Elsevier B. V. All rights reserved.
Protein phosphatase inhibition assays for okadaic acid detection in shellfish: Matrix effects, applicability and comparison with LC-MS/MS analysis
HARMFUL ALGAE
Authors: Garibo, Diana; Damaso, Esther; Eixarch, Helena; de la Iglesia, Pablo; Fernandez-Tejedor, Margarita; Diogene, Jorge; Pazos, Yolanda; Campas, Monica
Abstract
The applicability of the protein phosphatase inhibition assay (PPIA) to the determination of okadaic acid (OA) and its acyl derivatives in shellfish samples has been investigated, using a recombinant PP2A and a commercial one. Mediterranean mussel, wedge clam, Pacific oyster and flat oyster have been chosen as model species. Shellfish matrix loading limits for the PPIA have been established, according to the shellfish species and the enzyme source. A synergistic inhibitory effect has been observed in the presence of OA and shellfish matrix, which has been overcome by the application of a correction factor (0.48). Finally, Mediterranean mussel samples obtained from Ria de Arousa during a DSP closure associated to Dinophysis acuminata, determined as positive by the mouse bioassay, have been analysed with the PPIAs. The OA equivalent contents provided by the PPIAs correlate satisfactorily with those obtained by liquid chromatography-tandem mass spectrometry (LC-MS/MS). (c) 2012 Elsevier B.V. All rights reserved.