An introduction to on-section CLEM

An introduction to on-section CLEM

by European Molecular Biology Laboratory (EMBL) · View the channel on PSI

Life & Natural Systems Science — General & History PDNScientific equipment, experiments and techniquesPDNDMicroscopy
🎙 European Molecular Biology Laboratory (EMBL) 👥 16K 📅 November 28, 2017 ⏱ 11 min 👁 8K 📄 tutorial 🧭 2026-10-10
Available in: English (current) Français

Keywords

CLEMelectron microscopyfluorescencehigh pressure freezingcorrelation

Summary

This video provides a comprehensive introduction to the on-section correlative light and electron microscopy (CLEM) technique developed at EMBL. It explains how to localize a protein of interest within a cell by combining light and electron microscopy on the same thin section. The workflow begins with culturing cells on sapphire discs and high-pressure freezing to preserve ultrastructure. After freeze substitution with uranyl acetate in acetone, the samples are infiltrated with Lowicryl HM20 resin and polymerized. Sectioning is performed with an ultramicrotome, and sections are placed on copper grids. Fluorescent fiducial beads are applied to enable correlation. The grids are imaged first with a fluorescence microscope and then with an electron microscope, and the images are overlaid using the eC-CLEM plugin. The video details each step with practical advice, including handling of the samples, avoiding air bubbles, and optimizing bead density. It also discusses the advantages and limitations of the method, such as specimen size and initial fluorescence intensity. The presentation is clear and well-structured, making it a valuable resource for scientists interested in subcellular localization studies.

176 words

Critical Evaluation

Value of the Information & Strength of the Argument

The video offers high practical value as a step-by-step protocol for a specific CLEM method. The information is presented in a logical sequence, covering all critical aspects from sample preparation to image correlation. The argumentation is based on the demonstration of a validated experimental procedure, with attention to common pitfalls and troubleshooting advice. The method’s strengths and limitations are honestly acknowledged, enhancing the credibility of the content.

Scientific Rigor, Source Quality, Title Accuracy

The video demonstrates strong scientific rigor by referencing specific equipment (e.g., Leica AFS-2, ultramicrotome), reagents (e.g., Lowicryl HM20, TetraSpeck beads), and software (eC-CLEM plugin). It originates from EMBL, a leading research institution, and is consistent with established CLEM protocols. The title adequately matches the content, as the video serves as an introductory tutorial. The description provides links to additional resources, though no direct citations of external publications are made within the video itself.

155 words

Title / Content Match

The title accurately reflects the content, which is an introductory guide to the on-section CLEM technique.

Quality & Reliability

9/10

The video is produced by EMBL, a world-renowned research institution, and presents a detailed, step-by-step protocol with clear explanations and references to specific equipment and software. The method is presented with practical tips and limitations, reflecting a high level of expertise.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

Contribution & Novelties

The video presents a detailed, accessible protocol for on-section CLEM, emphasizing the preservation of fluorescence in resin to allow direct correlation of light and electron microscopy data. It offers practical tips on handling delicate samples, image acquisition, and correlation software. This educational resource is particularly valuable for researchers new to CLEM.

Pour aller plus loin :

  • Correlative light and electron microscopy — This Wikipedia article provides a broad overview of CLEM techniques and applications.
  • Cryofixation for high pressure freezing — Explains the principles of vitrification by high pressure freezing, a key step in the protocol.
  • Fluorescence microscope — Essential for understanding the light microscopy part of CLEM.
  • eC-CLEM plugin (no URL) — Software plugin used for correlation, part of the Icy platform; details available in scientific literature.

127 words

Radar Profile

The radar profile shows consistently high scores, with quality and reliability dominating, indicating a well-produced and trustworthy educational resource. Technical level is also high, while quantity of information remains solid, making it a balanced and comprehensive tutorial.

Reliability 9/10