Imaging Bunyavirus Infections by Transmission Electron Microscopy: Conventional Sample Preparation vs High-Pressure...

Area of Science:

• Cell Biology
• Virology
• Microscopy

Background:

• Transmission electron microscopy (TEM) is crucial for studying virus dynamics, including entry, replication, and egress.
• Conventional sample preparation for TEM involves chemical fixation, dehydration, and resin embedding, which can alter cellular structures.
• High-pressure freezing followed by freeze substitution (HPF/FS) offers improved preservation of cellular components compared to conventional methods.

Purpose of the Study:

• To compare the morphological details of viral structures obtained using conventional resin embedding versus HPF/FS.
• To evaluate the advantages, disadvantages, and applications of both sample preparation techniques for viral studies.
• To illustrate these methods using cells infected with Bunyamwera virus (BUNV).

Main Methods:

• Conventional sample preparation: chemical fixation, dehydration, resin infiltration, and polymerization.
• High-pressure freezing (HPF) followed by freeze substitution (FS), resin infiltration, and polymerization.
• Imaging ultrathin sections of Bunyamwera virus (BUNV)-infected cells using transmission electron microscopy.

Main Results:

• HPF/FS provides superior preservation of cellular and viral ultrastructure compared to conventional processing.
• Distinct morphological differences in viral structures were observed between the two preparation methods.
• TEM imaging of ultrathin sections revealed detailed viral morphogenesis and egress pathways.

Conclusions:

• HPF/FS is a valuable technique for high-resolution ultrastructural studies of viruses, offering better morphological fidelity.
• Conventional processing remains a viable, though less optimal, method for TEM studies of viral infections.
• Understanding the impact of sample preparation on ultrastructure is critical for accurate interpretation of viral dynamics.