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To Do• Electron Microscopy Lecture
• Results from Environmental Plates & Broths
• Serial Dilution & Streak Plates
• Fungi: make wetmounts & observe demo’s
• Observe gram stain demo’s/finish old slides
Relative Size of objects
Resolution Analogy
Resolution
Anatomy of a Wave
Properties of Light
• Wavelength: Length of a light ray; represented by the Greek letter lambda ()
• Equal to the distance between two adjacent crests or troughs of a wave
• Resolution: Refers to the ability to see two items as separate and discrete units
Properties of Light
• Resolving Power (RP): minimal distance two points can be distinguished as two points
• The smaller the distance between objects that can be distinguished, the greater the resolving power of the lens
• RP= /2(NA)
Microscope Comparison
Modern Scanning Electron Microscope
Limits of Resolution
• Eye: 0.2 mm = 200 microns = 200,000 nm
• BF scope: 0.0002 mm =0.2 microns = 200 nm
• TEM: 0.00001 mm = 0.01 microns = 10 nm
E . coli Brightfield
KM
Comparison of Electron Microscopes
E.coli SEM E. coli TEM
Resolution vs. Magnification
Light Microscope SEM
SEM
TEM
Type of Scope?
Type of Scope?
ID Microbe & Specific Scope
CDC, used with permission
Microscope comparison John Wiley
Results from Environmental Samples
• Learn how to interpret broth culture growth patterns
Broth comparison
uninoculated
Various Colored Colonies
Review Properties of Agar• Comes from Red algae
• Microbes usually don’t eat it
• Not toxic
• Melts at 100 C
• Solidifies at 40 C
Preparation of a pure Culture
4 Quadrant Streak Plate
1. swab
2. loop
3. loop
4. loop
Do right NOW
Quantitation of Bacteria
Serial Dilutions
Comparison of Serial Dilution Techniques
Pour Plate
Which of these plates would be the correct one to count? Why?
Countable number of colonies (20 to 200 per plate)
Serial Dilutions
Fungal Demo’s Gram Stain Demo’s
• Aspergillus Treponema pallidum
• Rhizopus Neisseria gonorrhoeae
• Penicillium Corynebacterium
• Candida
Aspergillus
100x 400x
KM
What are these?
KM400x
Rhizopus
KM100x
Penicillium
100x 400x
Candida
100x 400x
KM
Candida & staphylococci
KM
Fungal Demo’s Gram Stain Demo’s
• Aspergillus Treponema pallidum
• Rhizopus Neisseria gonorrhoeae
• Penicillium Corynebacterium
• Candida
Treponema
CDC, used with permission
Treponema
1000xKM Wikipedia Commons, used with permission
Diplococci of Neisseria gonorrhoeae (4087X)
TEM diplococci of Neisseria gonorrhoeae (96,051X)
Neisseria
1000x KM
Neisseria
1000x KM
Corynebacterium diphtheria
CDC, used with permission
Corynebacterium diphtheria—the cause of diphtheria
Corynebacterium
1000x KM
Fungal Demo’s Gram Stain Demo’s
• Aspergillus Treponema pallidum
• Rhizopus Neisseria gonorrhoeae
• Penicillium Corynebacterium
• Candida
www.udel.edu
ID Microbe & Specific Scope