The cell in absence of aggregation artifacts.

Area of Science:

• Cell Biology
• Electron Microscopy
• Biophysics

Background:

• Conventional resin embedding techniques, while foundational for electron microscopy, are known to introduce aggregation artifacts in biological specimens.
• Eduard Kellenberger pioneered methods to mitigate these artifacts, including low-temperature embedding and the use of hydrophilic resins.

Purpose of the Study:

• To compare the ultrastructural preservation of Zea mays meristem cells prepared using different electron microscopy techniques.
• To evaluate the impact of aggregation artifacts in conventional resin embedding versus cryo-electron microscopy of vitreous sections.

Main Methods:

• Preparation of Zea mays meristem cells via three methods: conventional resin embedding, low-temperature embedding of freeze-substituted samples, and cryo-sectioning of vitrified samples.
• Comparative electron microscopy analysis of cellular compartments, including the extracellular space, cytoplasm, and nucleoplasm, across the different preparation methods.

Main Results:

• Conventional resin sections displayed compact, irregular structures, suggesting a complex matrix formation due to aggregation artifacts.
• Cryo-sections of vitrified samples showed diffuse, homogeneous appearances, indicating minimal structural distortion and preservation of a hydrated state.
• Low-temperature embedding yielded intermediate results, highlighting a gradient of artifact influence.

Conclusions:

• Cryo-electron microscopy of vitreous sections offers superior preservation of cellular ultrastructure by avoiding aggregation artifacts inherent in resin embedding.
• Observed differences in cellular appearance are largely attributable to aggregation artifacts, not solely fixation or sectioning variations.