III. Microscopy and Staining Flashcards
most common microscope used in microbiology
Light Microscope
are stained to increase the difference between the refractive indexes of the specimen and the medium.
Specimens
used with the oil immersion lens to reduce light loss between the slide and the lens.
- Immersion oil
- Used in unstained cells are more productively observed
- shows a light silhouette of an organism against a dark background.
Darkfield, phase-contrast, or DIC microscopy
- used for stained smears.
Brightfield illumination
brings direct and reflected or diffracted light rays together (in phase) to form an image of the specimen on the ocular lens.
phase-contrast microscope
- specimens are first stained with fluorochromes and then viewed through a compound microscope by using an ultraviolet light source.
Fluorescence microscopy
- a specimen is stained with a fluorescent dye and illuminated with short-wavelength light.
- Using a computer to process the images, two-dimensional and three-dimensional images of cells can be produced.
Confocal microscopy
- a live specimen is stained with a fluorescent dye and illuminated with long-wavelength light.
Two-Photon Microscopy
- Thin sections of organisms can be seen in an electron micrograph produced using a
- Magnification: 10,000–100,0003. Resolving power: 10 pm.
Transmission electron microscope ( TEM )
- based on the interpretation of sound waves through a specimen.
- It is used to study living cells attached to surfaces such as cancer cells, artery plaque, and biofilms.
Scanning Acoustic Microscopy
Scanned-Probe Microscopy
Scanning tunneling microscopy (STM) and atomic force microscopy (AFM)
- Instead of light, a beam of electrons is used with an electron microscope.
- Instead of glass lenses, electromagnets control focus, illumination, and magnification.
Electron Microscopy
- Three-dimensional views of the surfaces of whole microorganisms can be obtained
- Magnification: 1000–10,0003. Resolution: 10 nm.
Scanning electron microscope ( SEM )
produce three-dimensional images of the surface of a molecule.
Scanning tunneling microscopy (STM) and atomic force microscopy (AFM)
