Spanish National Research Council 5 articles published in JoVE Engineering Surgical Techniques for Catheter Placement and 5/6 Nephrectomy in Murine Models of Peritoneal Dialysis Guadalupe Tirma González-Mateo1,2, Lucía Pascual-Antón1, Pilar Sandoval1, Abelardo Aguilera Peralta3, Manuel López-Cabrera1 1Molecular Biology Research Centre Severo Ochoa, Spanish National Research Council, 2IdiPAZ Research Institute, La Paz University Hospital, 3Princesa Research Institute, La Princesa University Hospital This article shows the method for the surgical placement in mice of an intraperitoneal catheter attached to an access port that is positioned at the back of the animal. Moreover, it explains the procedure for a 5/6 nephrectomy to resemble the uremic state of PD patients. Developmental Biology AFM and Microrheology in the Zebrafish Embryo Yolk Cell Maria Marsal1, Ignasi Jorba2, Elena Rebollo1, Tomas Luque2, Daniel Navajas2, Enrique Martín-Blanco1 1Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, 2Institute for Bioengineering of Catalonia, Universitat de Barcelona and CIBER Enfermedades Respiratorias The lack of tools to measure material properties and tensional parameters in vivo prevents validating their roles during development. We employed atomic force microscopy (AFM) and nanoparticle-tracking to quantify mechanical features on the intact zebrafish embryo yolk cell during epiboly. These methods are reliable and widely applicable avoiding intrusive interventions. Biology A Method to Assess Bacteriocin Effects on the Gut Microbiota of Mice Chrstine Bäuerl*1, Özgun C.O. Umu*2, Pablo E. Hernandez3, Dzung B. Diep4, Gaspar Pérez-Martínez1 1Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), 2Department of Food Safety and Infection Biology, Norwegian University of Life Sciences (NMBU), 3Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Complutense de Madrid (UCM), 4Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU) Bacteriocins are believed to play a key role in defining microbial diversity in different ecological niches. Here, we describe an efficient procedure to assess how bacteriocins affect gut microbiota composition in an animal model. Biochemistry Protein-tRNA Agarose Gel Retardation Assays for the Analysis of the N6-threonylcarbamoyladenosine TcdA Function Francisco J. Fernández1,2,3, Sara Gómez1, Sergio Navas-Yuste1, Miguel López-Estepa1, M. Cristina Vega1 1Department of Physical Chemical Biology, Center for Biological Research (CIB-CSIC), Spanish National Research Council (CSIC), 2Department of Immunology, Complutense University School of Medicine, 3Abvance Biotech srl A protocol is presented for the production of tRNA(UUU) and the analysis of tRNA(UUU) in complex with the enzyme TcdA by agarose gel retardation assays. Neuroscience In Utero Electroporation Approaches to Study the Excitability of Neuronal Subpopulations and Single-cell Connectivity Carlos G. Briz1, Marta Navarrete2, José A. Esteban2, Marta Nieto1 1Department for Molecular and Cellular Biology, Centro Nacional de Biotecnología (CNB-CSIC), 2Molecular Neurobiology Department, Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC-UAM) This manuscript provides protocols that use in utero electroporation (IUE) to describe the structural connectivity of neurons at the single-cell level and the excitability of fluorescently labeled neurons. Histology is used to characterize dendritic and axonal projections. Whole-cell recording in acute slices is used to investigate excitability.