Abstract
The outer surfaces of three microorganisms, Giardia lamblia, Enterococcus faecalis, and Proteus mirabilis, were investigated by cryo-immobilization followed by sublimation of extracellular ice and cryocoating with either Pt alone or Pt plus carbon. Cryocoated samples were examined at -125°C in either an in-lens field emission SEM or a below-the-lens field emission SEM. Cryocoating with Pt alone was sufficient for low magnification observation, but attempts to do high-resolution imaging resulted in radiolysis and cracking of the specimen surface. Double coating with Pt and carbon, in combination with high resolution backscatter electron detectors, enabled high-resolution imaging of the glycocalyx of bacteria, revealing a sponge-like network over the surface. High resolution examination of bacterial flagella also revealed a periodic substructure. Common artifacts included radiolysis leading to "cracking" of the surface, and insufficient deposition of Pt resulting in the absence of detectable surface topography.
Original language | English (US) |
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Pages (from-to) | 273-278 |
Number of pages | 6 |
Journal | Microscopy and Microanalysis |
Volume | 9 |
Issue number | 4 |
DOIs | |
State | Published - Aug 2003 |
Keywords
- Cryo-immobilization
- CryoFESEM
- Enterococcus faecalis
- Extracellular topography
- Field emission SEM
- Giardia lamblia
- Glycocalyx
- Proteus mirabilis