Published on August 23rd, 2022 in EMBO reports, this article questions the way that core facilities should be recognized in the scientific literature and their key contributions to data lifecycle. An initiative endorsed by France-BioImaging.

Core facilities are an integral part of the life science research landscape as providers of centralised access to technological resources and expertise. This article’s working group has estimated that between 40 and 80% of imaging, proteomics and genomics data at their institutes are generated at core facilities. The contribution of core facilities to scientific research and innovation must thus be accordingly recognised. In that respect, the most straightforward way is an acknowledgement. Unfortunately, the lack of formal rules still leaves core facilities being inadequately recognised. 

This article proposes that the recognition of core facilities should be deployed via two actions and implemented in two phases: first, with the systematic acknowledgement of core facilities in all scientific publications, and second, by including core facilities and their staff in data citations (Cousijn et al, 2018).

The first step can be accomplished at the manuscript-submission stage by asking the corresponding author to confirm if any data (and associated metadata) used in the manuscript originated from a core facility, and if yes, to identify the associated core facility. EMBO Press has recently included a question in the author checklist to confirm whether the work in the publication “benefited from core facilities” and that the core facility be acknowledged accordingly.

The next step would be to make it compulsory for authors to respond to such a query and explicitly identify the core facility and relevant data (and associated metadata). The MDAR (Materials, Design, Analysis, Reporting) form (Macleod et al, 2021), wherein one needs to provide information about data availability in the Analysis section, could likewise include a question to explicitly identify core facilities involved. Eventually, the information in the author checklist could be automatically fed into the acknowledgement section.

Acknowledging will have two key positive consequences: on the sustainability of core facilities and on their staff careers. In the absence of a high number of publications, particularly as lead or corresponding authors, acknowledgements are used as a measure of a core facility and its staff’s output and impact. Second, it further motivates and incentivizes core facility staff to actively contribute to scientific research. 

The acknowledgement of a core facility goes beyond professional courtesy: identifying the origin of data (and associated metadata) is essential for data traceability and reproducibility particularly since core facilities are major generators of data in life science research. 

Thanks to Jean SALAMERO, our “Action inter-infrastructures” mission officer, for contributing to this article. 

Full article on:

Acknowledging and citing core facilities

Katja Kivinen, Henri G A M van Luenen, Myriam Alcalay, Christoph Bock, Joanna Dodzian, Katerina Hoskova, Danielle Hoyle, Ondrej Hradil, Sofie Kjellerup Christensen, Bernhard Korn, Theodoros Kosteas, Mònica Morales, Krzysztof Skowronek, Vasiliki Theodorou, Geert Van Minnebruggen, Jean Salamero, Lavanya Premvardhan

EMBO reports (2022) 23: e55734
https://doi.org/10.15252/embr.202255734

Developed by the Serpico Inria-CNRS-Institut Curie Joint Team, member of the IPDM-BioImage Informatics node of France-BioImaging (FBI), this open-source framework could be a huge step forward in bioimaging management and analysis.

Bioimaging has a broad range of applications, addressing a variety of biological models at diverse scales of life. Thus, descriptions of novel computational approaches are often focused on target case studies. To tackle any scenario in biological imaging is a major challenge, that needs the conception and the development of a unified solution.

With this in mind, the BioImageIT project aims at providing a middleware that integrates data management with analysis using existing softwares (Omero, BioFormats, Fiji, napari, Scipy, pytorch…). The mission of BioImageIT was to design a graphical user interface (GUI) that allows any scientist without coding skills to annotate and analyze datasets using various software. By being user-centered, open-source and cross-platform (Windows, MacOS, Linux), BioImageIT created a management tool that is definitely accessible and well documented.

Started in late 2019, the project, funded by France-BioImaging, is now being deployed in 10 FBI imaging facilities. As it is a first step, the BioImageIT project have the ambition to expand the dissemination of the middleware throughout France and even further, Europe.

BioImageIT overview. a, Schematic view of BioImageIT architecture. The BioImageIT core is composed of data management and data processing functionalities. Users can access plugins by a script editor, Jupyter or the BioImageIT graphical interface (GUI). Data management functionalities exploit local files, remote files or databases such as OMERO. Data processing can perform computations in remote jobs, containers, or local runners. Image analysis is provided by plugins written in different languages. Developers can implement their own plugins in BioImageIT and design their own Graphical Interface. (b-i) LLSM processing workflow gathered in BioImageIT. Hela cell line expressing CD-M6PR-eGFP were stained with Tubulin TrackerTM Deep Red for Microtubules. b, Due to the geometry of LLS scanning, raw 3D images are skewed. c, g, First, realignment (deskew) of raw stacks is performed using Pycudadecon. d, h, Richardson Lucy deconvolution is performed using Pycudadecon. e, CD-M6PR-eGFP vesicles are tracked using Trackmate(FiJi). f, i, Deconvolved stacks and tracks are rendered using napari.

Prigent, S., Valades-Cruz, C.A., Leconte, L. et al. BioImageIT: Open-source framework for integration of image data management with analysis. Nat Methods (2022).
https://doi.org/10.1038/s41592-022-01642-9

Direct and simultaneous observation of transcription and chromosome architecture in single cells with Hi-M

Andrés M. Cardozo Gizzi, Sergio M. Espinola, Julian Gurgo, Christophe Houbron, Jean-Bernard Fiche, Diego I. Cattoni, Marcelo Nollmann

Simultaneous observation of 3D chromatin organization and transcription at the single cell level and with high spatial resolution may hold the key to unveil the mechanisms regulating embryonic development, cell differentiation and even disease. We have recently developed Hi-M, a technology that allows for the sequential labelling, 3D imaging and localization of multiple genomic DNA loci together with RNA expression in single cells within whole, intact Drosophila embryos. Importantly, Hi-M enables simultaneous detection of RNA expression and chromosome organization without requiring sample unmounting and primary probe re-hybridization. Here, we provide a step-by-step protocol describing the design of probes, the preparation of samples, the stable immobilization of embryos into microfluidics chambers, and the complete procedure for image acquisition. The combined RNA/DNA fluorescence in situ hybridization procedure takes 4-5 days including embryo collection. In addition, we describe image analysis software to segment nuclei, detect genomic spots, correct for drift and produce Hi-M matrices. A typical Hi-M experiment takes 1-2 days to complete all rounds of labelling and imaging and 4 additional days for image analysis. This technology can be easily expanded to investigate cell differentiation in cultured cells, or organization of chromatin within complex tissues.

DOI https://doi.org/10.1038/s41596-019-0269-9

Contact: Marcelo Nolmann marcnol@gmail.com

ATP-driven separation of liquid phase condensates in bacteria

B. Guilhas, J.C. Walter, J. Rech, G. David, N.-O. Walliser, J. Palmeri, C., Mathieu-Demaziere, A. Parmeggiani, J.Y. Bouet, A. Le Gall1, M. Nollmann

Liquid-liquid phase separated (LLPS) states are key to compartmentalise components in the absence of membranes, however it is unclear whether LLPS condensates are actively and specifically organized in the sub-cellular space and by which mechanisms. Here, we address this question by focusing on the ParABS DNA segregation system, composed of a centromeric-like sequence (parS), a DNA-binding protein (ParB) and a motor (ParA). We show that parS-ParB associate to form nanometer-sized, round condensates. ParB molecules diffuse rapidly within the nucleoid volume, but display confined motions when trapped inside ParB condensates. Single ParB molecules are able to rapidly diffuse between different condensates, and nucleation is strongly favoured by parS. Notably, the ParA motor is required to prevent the fusion of ParB condensates. These results describe a novel active mechanism that splits, segregates and localises non-canonical LLPS condensates in the sub-cellular space.

Guilhas et al. revealed that the bacterial DNA segregation apparatus behaves as a non-canonical phase separation system. This apparatus employs an ATP-powered motor that splits nanometer-sized condensates and localizes them robustly within the nucleoid to ensure faithful transmission of genetic material.

DOI: https://doi.org/10.1016/j.molcel.2020.06.034

Contact: Marcelo Nolmann marcnol@gmail.com

The ability to communicate effectively with each other is one of the strongest predictors for our chances to get ahead in life. In their latest publication in Science Advances, scientists and engineers from IGF-Montpellier (CNRS, INSERM, Univ. Montpellier), IPAM platform (BioCampus Montpellier, France-Bioimaging Montpellier Node) and ARO-Israel demonstrated that this also holds true for GnRH neurons.

In humans and all vertebrates, species survival depends on a critical step during embryonic development: the migration of a small subset of GnRH neurons (about 2,000 in humans and less than 100 in fish) from the nose to the brain where they join the hypothalamus to control reproduction. Their latest results unveiled that GnRH neurons make a pause at the nose-brain frontier where they function as an inter-hemispheric network that is isolated from the rest of the brain. Only neurons that integrate into the network and are able to communicate with their neighbors will finally cross the barrier and make their way into the brain, towards their hypothalamic destination.

In other words, these GnRH neurons, that are critical for species persistence, face the same challenges like other immigrants: they must learn to communicate effectively if they are to integrate into their new world.

In this study, in vivo 2-photon microscopy was a key tool for:

  • Long term imaging with minimal bleaching and phototoxicity
  • Upright configuration enabling dorsal imaging of the fish in its natural position
  • Long-distance water-immersion objectives allowing imaging of deep tissue structures without sacrificing image quality
  • Fast calcium imaging
  • Imaging of red GECI using the higher wavelengths
  • Precise cell ablation
  • Photoactivation of ChR2 while monitoring Ca in the red channel
A graphical model illustrating the migration of a single GnRH neuron (marked by black border) from the nasal placode into the zebrafish brain.

M. Golan, J. Boulanger-Weill, A. Pinot, P. Fontanaud, A. Faucherre, D. S. Gajbhiye, L. Hollander-Cohen, T. Fiordelisio-Coll, A. O. Martin, P. Mollard, Synaptic communication mediates the assembly of a self-organizing circuit that controls reproduction. Sci. Adv. 7, eabc8475 (2021). doi: 10.1126/sciadv.abc8475

Contact: Patrice Mollard, IGF, Montpellier patrice.mollard@igf.cnrs.fr

During embryonic development, cells take on increasingly precise roles in the body as they divide. Be they skin cells, muscle cells or neurons, the different cell types that make up the embryo emerge gradually from a very fine orchestration of their positions and identities, coordinated by the signals they exchange with each other. Like us, the cells need to “talk” to each other to make decisions.

Screaming or whispering: the embryonic cell dilemma

In vertebrate embryos, cells have a very dynamic behaviour. They move around, exchange their neighbours or migrate over long distances. The signals they exchange therefore need to have a long range, which could be characterized as “shouting”. The study of the embryonic development of a sea squirt, a small marine animal with optically transparent embryos, has enabled scientists from several teams at CNRS and INRIA in France, in collaboration with a team from the European Molecular Biology Laboratory (EMBL, Germany), to capture and describe in detail a more discreet mode of cell communication.

The scientists recorded the development of live embryos every two minutes with a new-generation « light-sheet » microscope. They then created software to automatically detect each cell and analyze its position, shape and neighbours up to an advanced stage of development. This work revealed an unusually reproducible mode of development, in which the same cell can be found in the same position across all embryos and where cells move very little in relation to each other. The authors of the study then annotated the films thus made with information on the cell type and the molecular signals emitted by each cell. Using mathematical modelling to integrate the quantitative description of the embryonic geometry with these annotations, their work suggest that cells communicate with very short-range signals. Moreover, the interpretation of these signals is modulated by the area of the contacts between cells. Unlike vertebrates, the cells of ascidian embryos thus have a static and fixed behaviour and the range of their “whispered” signals is very small.

Top: embryonic development of an ascidian from egg to tadpole. The part framed in white is the part of embryogenesis that we have imaged and then segmented (below, segmented cells coloured according to their cell fate). The lower part of the figure illustrates that the light green cells “whisper” instructions to their immediate neighbours by short-range signals.

This study indicates that the dynamics of cell movement varies greatly between animals and that these different modalities could be strongly related to the range of signals that the cells exchange with each other. By extending the repertoire of cellular communication mechanisms, this work opens new perspectives on the understanding of self-organization strategies of living forms.

Article: L. Guignard*, U.-M. Fiuza*, B. Leggio, J. Laussu, E. Faure, G. Michelin, K. Biasuz, L. Hufnagel, G. Malandain, C. Godin#, P. Lemaire# (2020) Contact-area dependent cell communications and the morphological invariance of ascidian embryogenesis (Science, July 10 2020 issue, https://science.sciencemag.org/content/369/6500/eaar5663)

2 recent publications using the laser irradiation and photoablation systems available on the MRic facility from the Bretagne-Loire Node are presented here:

  • Esmangart de Bournonville and Le Borgne (IGDR) characterized the assembly and interactions of tricellular junction components in Drosophila epithelial cytokinesis using laser ablation on a SP5 confocal. Their article entitled “Interplay between Anakonda, Gliotactin, and M6 for Tricellular Junction Assembly and Anchoring of Septate Junctions in Drosophila Epithelium” was published last august in Current Biology (https://doi.org/10.1016/j.cub.2020.07.090).
  • Rebecca Smith, post-doc in Sébastien Huet’s team (IGDR) in collaboration with Szilvia Juhász from Gyula Timinszky’s team (Szeged, Hungary) used laser irradiation to study chromatin remodeling following DNA damage. Their paper entitled “The chromatin remodeler ALC1 underlies resistance to PARP inhibitor treatment” has just been accepted in Science Advances.