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