Summary

The Advanced Light Microscopy Unit (ALMU) of the CRG and UPF serves as a core facility for high-end light microscopy for PRBB researchers. A range of instruments with unique capabilities fully covers the spectrum of advanced imaging applications from thick tissue reconstruction to fast in-vivo imaging to the sensitive detection of very faint signals of single molecules. The staff of the facility provides advice in the initial experiment planning, training of the researchers on the instruments and assistance with the subsequent data analysis. It is the aim of the facility to provide a link for the biological questions of researchers to the full capabilities of advanced light microscopy at the organismic, cellular and molecular level. Methods available in the facility include super-resolution microscopy by stimulated emission depletion (STED) and Ground State Depletion Imaging Microscopy (GSDIM), optical sectioning (single photon and multi-photon microscopy), spectral imaging, in-vivo time-lapse imaging, Total Internal Reflection Fluorescence (TIRF) Microscopy and methods for the study of molecular properties and interactions like Fluorescence Correlation Spectroscopy (FCS), Fluorescence Lifetime Imaging Microscopy (FLIM), Fluorescence Resonance Energy Transfer (FRET) detection, Fluorescence Recovery after Photobleaching (FRAP) and confocal and widefield screening microscopy. Additionally, dedicated software packages for data visualization and analysis are available for 3D rendering, particle tracking and image analysis.

In 2015, the total booked microscope usage time of the unit reached 18600 hours in approx. 4700 separate bookings. This corresponds to approximately seven hours of daily usage on the bookable microscope systems plus many additional hours on equipment without mandatory booking and on special equipment. During the year, 118 users from 29 CRG research groups and 46 users from 22 UPF-CEXS groups have used the unit. Additionally, the unit was used by 38 users from 19 groups of other PRBB institutes and one company and for projects from external visitors. On average, 80 investigators use the unit every month.

The technology offer of the unit was kept up-to-date by the installation of the latest version of Stimulation Emission Depletion (STED) technology, a Leica SP8 STED 3X system with white light laser excitation and three depletion lasers (592, 660 and 775nm) for time-gated and pulsed STED imaging that cover the whole range of fluorophore labels and allow also the imaging of living samples. This equipment was co-financed with FEDER funds from MINECO (CREG13-4E-2489).

As management and processing and analysis of image data is an ever more urgent challenge for microscopy facilities, ALMU has started to work on this issue together with the German technology provider Acquifer AG and has become a reference site for the HIVE technology for data storage and management and processing.

Timo Zimmermann is since 2015 the Spanish representative for Biological Imaging in the Interim Board of the ESFRI project Euro-BioImaging. He is also a work package leader in the H2020 INFRADEV Euro-BioImaging two-year Preparatory Phase II project that was awarded in 2015. The microscopy unit participates in two highly evaluated Spanish node proposals for Euro-BioImaging, for super-resolution microscopy (with the Photonic Sciences Institute ICFO) and for in-vivo and intravital imaging (with the University of Barcelona and IRB Barcelona). Both nodes have been proposed by the Spanish ministry for operation during the current interim phase of the project and have at the end of the year been ratified by the Euro-BioImaging interim board.

All members of the staff are frequently participating as speakers and instructors in masters courses from the CRG and UPF, as well as in many conferences and microscopy courses both at the PRBB as well as at other institutions, nationally and internationally. A specific highlight among these activities was the organization (by Timo Zimmermann and Julien Colombelli from IRB, Barcelona) of the 15^th international meeting of the European Light Microscopy Initiative (ELMI) from the 19^th to the 22^nd of May in Sitges. The conference was attended by 413 international imaging specialists and was preceded by an Imaging Core Facility Satellite Meeting with 193 participants. During the meeting 23 invited and 16 selected speakers presented their work and the participants could inform themselves on the latest technology offers at 39 sales exhibitions and also 53 applied workshops that were offered by the participating companies.