A C. elegans model for neurodegeneration in Cockayne syndrome.

Cockayne syndrome (CS) is a congenital syndrome characterized by growth and mental retardation, and premature ageing. The complexity of CS and mammalian models warrants simpler metazoan models that display CS-like phenotypes that could be studied in the context of a live organism. Here, we provide a characterization of neuronal and mitochondrial aberrations caused by a mutation in the csb-1 gene in Caenorhabditis elegans. We report a progressive neurodegeneration in adult animals that is enhanced upon UV-induced DNA damage. The csb-1 mutants show dysfunctional hyperfused mitochondria that degrade upon DNA damage, resulting in diminished respiratory activity. Our data support the role of endogenous DNA damage as a driving factor of CS-related neuropathology and underline the role of mitochondrial dysfunction in the disease

A Customized Light Sheet Microscope to Measure Spatio-Temporal Protein Dynamics in Small Model Organisms

We describe a customizable and cost-effective light sheet microscopy (LSM) platform for rapid three-dimensional imaging of protein dynamics in small model organisms. The system is designed for high acquisition speeds and enables extended time-lapse in vivo experiments when using fluorescently labeled specimens. We demonstrate the capability of the setup to monitor gene expression and protein localization during ageing and upon starvation stress in longitudinal studies in individual or small groups of adult Caenorhabditis elegans nematodes. The system is equipped to readily perform fluorescence recovery after photobleaching (FRAP), which allows monitoring protein recovery and distribution under low photobleaching conditions. Our imaging platform is designed to easily switch between light sheet microscopy and optical projection tomography (OPT) modalities. The setup permits monitoring of spatio-temporal expression and localization of ageing biomarkers of subcellular size and can be conveniently adapted to image a wide range of small model organisms and tissue samples.MR, GZ and AZ acknowledge funding from the Projects “Skin-DOCTor” Grant No. 1778 and “Neureka!” Grant No. LSF7-341 implemented under the "ARISTEIA" and "Supporting Postdoctoral Researchers" Actions respectively, of the "OPERATIONAL PROGRAMME EDUCATION AND LIFELONG LEARNING", (http://www.espa.gr/en/pages/staticOPEducationandLifelongLearning.aspx), which is co-funded by the European Social Fund and National Resources and from the EU Marie Curie Initial Training Network “OILTEBIA”, Grant No. PITNGA-2012-317526 (http://ec.europa.eu/research/mariecurieactions/, http://gdo.uc3m.es/oiltebia/index. php?option = com_content&view = frontpage). JR acknowledges support from EC FP7 CIG grant HIGHTHROUGHPUT TOMO PICIG12-GA-2012-333632, (http://cordis.europa.eu/projects/333632), and Spanish MINECO grant MESO-IMAGING FIS2013-41802-R, (https://sede.micinn.gob.es/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

3D imaging of biofilms on implants by detection of scattered light with a scanning laser optical tomograph

Biofilms – communities of microorganisms attached to surfaces – are a constant threat for long-term success in modern implantology. The application of laser scanning microscopy (LSM) has increased the knowledge about microscopic properties of biofilms, whereas a 3D imaging technique for the large scale visualization of bacterial growth and migration on curved and non-transparent surfaces is not realized so far

Microscopic Optical Projection Tomography In Vivo

We describe a versatile optical projection tomography system for rapid three-dimensional imaging of microscopic specimens in vivo. Our tomographic setup eliminates the in xy and z strongly asymmetric resolution, resulting from optical sectioning in conventional confocal microscopy. It allows for robust, high resolution fluorescence as well as absorption imaging of live transparent invertebrate animals such as C. elegans. This system offers considerable advantages over currently available methods when imaging dynamic developmental processes and animal ageing; it permits monitoring of spatio-temporal gene expression and anatomical alterations with single-cell resolution, it utilizes both fluorescence and absorption as a source of contrast, and is easily adaptable for a range of small model organisms

Detecting and quantifying stress granules in tissues of multicellular organisms with the Obj.MPP analysis tool

International audienceStress Granules (SGs) are macromolecular assemblies induced by stress and composed of proteins and mRNAs stalled in translation initiation. SGs play an important role in the response to stress and in the modulation of signaling pathways. Furthermore, these structures are related to the pathological ribonucleoprotein (RNP) aggregates found in neurodegenerative disease contexts, highlighting the need to understand how they are formed and recycled in normal and pathological contexts. Although genetically tractable multicellular organisms have been key in identifying modifiers of RNP aggregate toxicity, in vivo analysis of SG properties and regulation has lagged behind, largely due to the difficulty of detecting SG from images of intact tissues. Here, we describe the object detector software Obj.MPP and show how it overcomes the limits of classical object analyzers to extract the properties of SGs from wide-field and confocal images of respectively C. elegans and Drosophila tissues. We demonstrate that Obj.MPP enables the identification of genes modulating the assembly of endogenous and pathological SGs, and thus that it will be useful in the context of future genetic screens and in vivo studies. This article is protected by copyright. All rights reserved

Απεικόνιση του νηματώδους C. elegans με χρήση οπτικής προβολικής τομογραφίας.

Small sample spatial in vivo imaging techniques such as confocal microscopy, micro MRT (µMRT), Selective Plane Illumination Microscopy (SPIM) or contrast enhanced techniques such as DICM (Differential Interference Contrast Microscopy) are common tools for imaging fluorescent expression in the nematode Caenorhabditis elegans. However, these methods have limited capacity for high resolution, rapid, whole body 3D microscopic imaging and/or imaging of multiple contrast agents. The recently developed approach of Optical Projection Tomography (OPT) enables 3D visualization of whole specimens up to several millimetres in size as has already been shown in zebra fish, chick and mouse embryos. This is achieved by applying a filtered back projection algorithm on images taken from equidistant angles of a rotating specimen with magnification dependent resolution, down to 1-5 µm. Here I present a modified OPT setup for 3D imaging of GFP expressing neuronal cells in C. elegans. This study demonstrates that this novel technique allows rapid acquisition of whole-animal fluorescent expression patterns in the nematode with high accuracy. OPT visualization can easily be adapted to image multiple tissues and cell types, with a variety of chromophores, that allow multi-colour projections, in the nematod