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Welcome to the Leschziner Lab's Tutorials Wiki

In these pages you will find tutorials designed to explain, in an accessible way, some of the principles behind the techniques used in our lab. They range from the very general (How does a microscope work?) to very specific approaches used in Three-Dimensional Electron Microscopy (3D-EM). This wiki is, by definition, a "work in progress"; we will periodically add new material and update what's already here. Blue links are for tutorials already available while red ones are for those we are still developing.

We hope you find the material useful and welcome feedback on how to improve it. To give us feedback, please see the discussion tab at the top of the page, or e-mail us.

Introduction

In the Leschziner Lab, we use electron microscopy to study structures of macromolecules. In particular, we look at single particles and use the techniques described in the sections below to generate three-dimensional structures of the proteins or protein complexes of interest. In addition to the study of protein structure, our lab is interested in improving techniques for 3D-EM.

General imaging principles

These conventions and basic physics concepts are fundamental tools for understanding electron imaging.

• Light optics
• Microscope Ray Tracing
• Phase Contrast
• Depth of Field

Electron imaging

There are many caveats to imaging with electrons as opposed to photons.

• What is an Electron Microscope?
• History of the Electron Microscope
• Types of Signals
• Electron optics
• The Weak-Phase Object Approximation
• Contrast
• Ewald Sphere
• Aberrations
• Special Imaging Techniques

Electron Microscopy of Macromolecules

• Sample Preparation
• Special Considerations

Three-dimensional reconstruction by EM

A "30 Second Overview" of three-dimensional EM reconstruction.

Basics

• Central Section Theorem
• Back Projection

Existing Reconstruction Methods

• Angular Reconstitution (AR)
• Random Conical Tilt (RCT)
• Orthogonal Tilt Reconstruction (OTR)

Software Available

An overview of the currently available software, links, and general descriptions.

Resolution

The concept of resolution in electron microscopy has brought out several debates in the past.

Hardware Innovations to the Electron Microscope

Some new, some old, there are many aspects of the microscope that may be changed, ostensibly altering the physics of image formation for the better.

• CMOS
• Phase Plates

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