| Techniques in Microbiology |
Techniques in Microbiology
Microscopy:
- Electron Microscopy: uses electrons to create an image of
the specimen.
- Brightfield Microscopy: specimen is visualized after the
light has passed through it.
- Dark Field Microscopy: used when staining a sample is
difficult or impossible.
- Inverted Microscope: lenses are under the stage point upward
used for thick samples.
- Upright Light Microscope: lenses are above the specimen
point down.
Slide Preparation and Cell Stains:
- Wet Mount slide preparation: can be done
with specific dyes or water.
- Common Laboratory Stains: Gram-Negative
stain with safranin and appear red.
- Gram-Positive: crystal violet sometimes
methylene blue.
Aseptic Techniques: Method to collect, grow and preserve a
sample such that no other microbes are introduced or lost from the
original culture.
Agar Plates:
- Streak Plate Procedure: plate is
streaked in a zig zag patter to dilute a
sample spread out sample for the purpose of
isolating individual colonies.
- Selective Agar: growth medium with
chemicals mixed in to select bacteria based
on specific physiological characteristics
e.g. antibiotic resistance.
- Quantification: Colony forming units (CFU) method to
determine the number of bacteria in ample.
- Dilution Plating: successive dilution of a sample to
quantify and isolate single colonies.
- Isolation of pure bacteria colonies: method to create a pure
culture.
- Colony Characteristics: Shape, size, morphology and growth
patterns.
- Phage Quantification: PFU, plaque forming units, clear
areas of growth on a bacterial lawn plated on agar which
indicate the presence and numbers of phage present.
DNA Methods
- PCR: Polymerase Chain Reaction, method
used to amplify specific DNA sequences for
ease of identification and sequencing.
- Electrophoresis: DNA sample place in a
gel substrate between two electrodes. The
charge and size of the DNA determines how
fast the DNA migrates in the electrical
field.
- DNA sequencing: Method to determine the
order of which nucleotides are arranged on a
strand of DNA.
|
|
