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Shape changes in Escherichia coli B/r A during agar filtration
1Hubert H. Humphrey Center for Experimental Medicine and Cancer Research, Hebrew University Faculty of Medicine, Jerusalem, Israel.
Cytometry
|January 1, 1993
Summary
Electron microscopy preparation causes Escherichia coli shape distortion. Dehydrated cells show increased width and decreased length compared to live bacteria, impacting 3D shape modeling.
Area of Science:
- Microbiology
- Cell Biology
- Microscopy Techniques
Background:
- Accurate bacterial cell dimensions are crucial for understanding cellular processes.
- Electron microscopy (EM) preparation methods can introduce artifacts, including shape distortion.
- Previous studies have not fully quantified drying-induced shape changes in Escherichia coli.
Purpose of the Study:
- To investigate and quantify shape distortion in Escherichia coli B/r A cells during EM preparation.
- To develop a 3D model of bacterial cell shape based on quantitative measurements.
- To estimate the effects of sample drying on cell dimensions.
Main Methods:
- Utilized agar filtration for sample preparation of 1,552 Escherichia coli cells.
- Employed low-angle shadow casting with polystyrene latex spheres for dimensional analysis.
- Performed statistical analysis of cell projections in nonshadow-cast preparations to assess drying effects.
Main Results:
- Dehydrated Escherichia coli cells exhibited an average width of 450 nm, approximately 20 nm greater than live cells.
- The average length of dehydrated cells was 1,398 nm, about 40 nm less than live cells.
- Quantitative data provided a basis for a 3D model of bacterial cell shape.
Conclusions:
- Agar filtration and drying during EM preparation induce significant shape distortion in Escherichia coli.
- The observed dimensional changes (increased width, decreased length) must be considered when interpreting EM data.
- Accurate 3D cell models require accounting for preparation-induced artifacts.