References genes for qRT-PCR in guaraná (Paullina cupana var. sorbilis)

Gene expression has been extensively studied in plant science research, mainly for the assessment of plant stress responses. Real-time-quantitative polymerase chain reaction (RT-qPCR) is an important tool for obtaining this information because it is a quick and easy technique to acquire a large amount of molecular data for both model and non-model plants. For a successful RT-qPCR analysis, gene expression should be carefully normalised. Genes involved in essential biological processes that exhibit constitutive expression are commonly selected as internal standards to normalise RT-qPCR experiments. In this study, the transcription profiles of 13 candidate reference genes for RT-qPCR were evaluated in three guarana cultivars (BRS-Amazonas, BRS-Maués and BRS-Luzéia) using different tissues (vegetative and fruit) in varying developmental stages. Two different algorithms, NormFinder and GeNorm, were utilised to assess gene stability. In general, the two algorithms did not select the same pairs of genes for all analysed conditions. For the largest group (the fruits of all cultivars), NormFinder selected the pair EF1A/UBQ, whereas GeNorm chose ACT/GAPDH as the best normalising genes. Thus, we recommend the use of at least four reference genes for the normalisation of gene expression in guarana plant studies. © 2015, Botanical Society of Sao Paulo

Hepatic microcirculation and mechanisms of portal hypertension.

The liver microcirculatory milieu, mainly composed of liver sinusoidal endothelial cells (LSECs), hepatic stellate cells (HSCs) and hepatic macrophages, has an essential role in liver homeostasis, including in preserving hepatocyte function, regulating the vascular tone and controlling inflammation. Liver microcirculatory dysfunction is one of the key mechanisms that promotes the progression of chronic liver disease (also termed cirrhosis) and the development of its major clinical complication, portal hypertension. In the present Review, we describe the current knowledge of liver microcirculatory dysfunction in cirrhotic portal hypertension and appraise the preclinical models used to study the liver circulation. We also provide a comprehensive summary of the promising therapeutic options to target the liver microvasculature in cirrhosis