Suchergebnisse

Ausgehend vom Verhältnis zwischen Biologie und allgemeiner Bildung sowie Aspekten der Wissenschaftspropädeutik formulieren die Autoren spezifische Aufgaben eines Kerncurriculums für den Biologieunterricht der Sekundarstufe II, bestehend aus den folgenden Teilen. 1. den Ausweis zentraler Inhalte und Methoden des Faches, die einen verbindlichen Kernbereich umreißen und exemplarische Vertiefung ermöglichen; 2. die Formulierung der durch den Fachunterricht zu erwartenden Kompetenzen; 3. die Beschreibung geeigneter Lehr-Lernformen. Diese Aufgaben werden von den Verfassern abgehandelt, wobei die Vernetzung von Wissen und das Denken in Systemen eine wichtige Rolle spielen. (DIPF/Orig./Ba.).

Light sheet fluorescence microscopy (LSFM) is rapidly becoming an essential technology for mesoscopic imaging of samples such as embryos and adult mouse organs. However, LSFM can suffer from optical artifacts for which there is no intrinsic solution. The attenuation of light due to absorbing material causes "shadow" artifacts along both the illumination and detection paths. Several approaches have been introduced to reduce this problem, including scanning illumination and multi-view imaging. However, neither of these approaches completely eliminates the problem. If the distribution of the absorbing material is complex, shadows cannot be avoided. We introduce a new approach that relies on multi-modal integration of two very different mesoscopic techniques. Unlike LSFM, optical projection tomography (OPT) can operate in transmission mode to create a voxel map of the 3D distribution of the sample's optical attenuation. Here, we demonstrate a hybrid instrument (OPTiSPIM) that can quantify this attenuation and use the information to correct the shadow artifacts of LSFM. ; The research was funded in part by the European Union's 7th Framework VIBRANT project (No. 228933 of the FP7-NMP) and the Sinergia project (CRII3_125477) of the Swiss National Science Foundation (SNSF). We acknowledge support from the Spanish Ministry of Economy and Competitiveness, "Centro de Excelencia Severo Ochoa 2013–2017" and from the CERCA Programme/Generalitat de Catalunya.

We present the implementation of a combined digital scanned light-sheet microscope (DSLM) able to work in the linear and nonlinear regimes under either Gaussian or Bessel beam excitation schemes. A complete characterization of the setup is performed and a comparison of the performance of each DSLM imaging modality is presented using in vivoCaenorhabditis elegans samples. We found that the use of Bessel beam nonlinear excitation results in better image contrast over a wider field of view. ; This work is supported by the Generalitat de Catalunya grant 2009-SGR-159, the Spanish government grants TEC2009-09698 and SAF2008-00211, the EU project STELUM (FP7-PEOPLE-2007-3-1-IAPP, 217997), the Swiss National Science Foundation (SNSF) Sinergia project grant CRSII3_125447, the FP7-NMP VIBRANT project grant CP-IP 228933-2, the NoE P4L and Laserlab optobio. Jacob Licea-Rodriguez acknowledges CONACYT Mexico for supporting his stay at ICFO through a mixed fellowship. This research has been partially supported by Fundació Cellex Barcelona and was mainly conducted at ICFO's "Super-Resolution Light Microscopy and Nanoscopy Facility"

Mouse models of Streptozotocin (STZ) induced diabetes represent the most widely used preclinical diabetes research systems. We applied state of the art optical imaging schemes, spanning from single islet resolution to the whole organ, providing a first longitudinal, 3D-spatial and quantitative account of β-cell mass (BCM) dynamics and islet longevity in STZ-treated mice. We demonstrate that STZ-induced β-cell destruction predominantly affects large islets in the pancreatic core. Further, we show that hyperglycemic STZ-treated mice still harbor a large pool of remaining β-cells but display pancreas-wide downregulation of glucose transporter type 2 (GLUT2). Islet gene expression studies confirmed this downregulation and revealed impaired β-cell maturity. Reversing hyperglycemia by islet transplantation partially restored the expression of markers for islet function, but not BCM. Jointly our results indicate that STZ-induced hyperglycemia results from β-cell dysfunction rather than β-cell ablation and that hyperglycemia in itself sustains a negative feedback loop restraining islet function recovery. ; The authors thank Lars Haag and Lisa Sjöwall at Karolinska Institutet's electron microscopy shared facility for providing TEM images. Dr. S. Willekens is acknowledged for help with editing of the manuscript. This project was funded by the Swedish Research Council, the Kempe foundations, Umeå University, Lenanders stiftelse, The strategic Research program in Diabetes at Karolinska Institutet, the Novo Nordisk Foundation, the Swedish Diabetes Association, the Family Knut and Alice Wallenberg Foundation, Diabetes Research and Wellness Foundation, the Stichting af Jochnick Foundation, the Family Erling-Persson Foundation, Berth von Kantzow's Foundation, the Skandia Insurance Company, Ltd., ERC-2013-AdG 338936-BetaImage, the European Union's Seventh Framework Program under grant agreements nos. 289932 and 613879.