This collection aims to disseminate the research in Molecular and Cellular Biology carried out by groups of the University of Jaén, in order to to be used as a work of reference for students of Biotechnology and Biomedicine. The book comprises six chapters dealing with a wide array of techniques and fundaments of Molecular Biology. These range from microscopy to techniques of molecular biology for the detection of verticilium, systems biology or eukaryotic RNA polymerases, microRNA or nitric oxide as regulator of cellular stress.