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Always read directions on how to prepare the agar! On the petri dish, write this on the agar side:

Your Name

Date

Time

Sample (Example: Ms. Fusco’s door handle)

DO NOT WRITE ON THE LID

Plating Techniques - METHOD 1: Triple-Z - This should give you isolated colonies.

1. Draw T on bottom of plate.

2. Flame sterilize inoculating loop, let cool 10 seconds

3. Pick up culture with loop.

4. Streak like a z-method back and forth in quadrant 1. DO NOT CROSS your T.

5. Flame sterilize and let cool

6. Drag inoculating loop through the end of quadrant 1 into quadrant 2.

7. Keep streaking in quadrant 2 with a z pattern. DO NOT CROSS ANY T again.

8. Flame sterilize, let cool

9. Drag inoculating loop through the end of quadrant 2 into quadrant 3.

10. Keep streaking in quadrant 3 with a z pattern. DO NOT CROSS the T again

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How Do We Grow Bacteria?
1. First, we need to make sure we practice aseptic technique. 2.Second, we need a media to grow them on 3. Third, we’ll need to wipe surfaces with a sterile applicator (looks like a really long Q-Tip or cotton swab).4. Fourth, we would inoculate the agar plate using a spreading technique.

Fifth, wrap plates in parafilm and incubate 48-72 hours!
Nutrients for Microbes! - Different media can have different nutrients that grow specific bacteria
Different Kinds! - LB Agar

YMA

Potato Dextrose

MacConkey Agar

Sheep’s Blood

Identification! - Narrowing down growth allows microbiologists to identity their cultures

Types of Agar
LB Agar - Common, Not very selective
Potato Dextrose - Grows both bacteria and fungi
Yeast-Mannitol - Used for soilmicrobiology

Sheep’s Blood - Determines type of hemolysis (breaking down blood)
MacConkey - Selects for Gram (-) bacteria and lactose fermentation

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Chain of Infection - Organism → Reservoir →

Portal of Exit → Transmission → Portal of Entry → Susceptible Host
Spread of Infection
Airborne - Long distance, remain suspended in air up to 6ft - Measles, TB, Chickenpox
Common Vehicle - Transfer by contaminated source - Salmonella
Vector-Borne - Transfer from host (carrier) → victim - Malaria (mosquitoes)
Direct Contact - Person/Person, Animal/Person, Pregnancy -     Rabies, HIV, Ebola, Lice, STDs
Droplet - Close proximity, coughing, sneezing, talking - Pertussis, Flu, TB

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Structure - Consists of a nucleic acid. DNA or RNA . This is its genetic material. Single or double stranded. Outer layer is the...

Capsid: rigid structure to withstand harsh environments.

Envelope: can only survive in aqueous solutions (usually transmitted via fluids)
Shapes
Complex, Bacteriophage: A virus that infects bacteria)
Helical/Filamentous -Tobacco mosaic virus, Ebola
Spherical -COVID-19, Influenza, Hepatitis B and Envelope Polyhedral. Poliovirus, adenovirus, rhinovirus

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Gram Staining
Add crystal violet stain, Add iodine, Rinse gently with ethyl alcohol, Counterstain with safranin, Gram + will be violet/blue, Gram - will be pink/red
Gram + - Thick peptidoglycan layer
Gram - - Thin/no peptidoglycan layer
AEROBIC Bacteria - Catalase Test
Catalase: Enzyme produced by bacteria that uses OXYGEN
A positive catalase test will have bubbles present
A negative catalase test will have no reaction
Identifying AEROBIC Bacteria - Thioglycollate Test

1. Obligate Aerobic: Love O2

2. Obligate Anaerobic: Avoid O2

3. Facultative: Prefer O2, but not hurt by the lack of O2

4. Microaerophiles: Low O2 levels

5. Aerotolerant: They do not care

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Bacilli - Rod-shaped

Important Examples: Streptobacillus, Bacillus

Cocci - Round, spherical

Important Examples:Staphylococci,Streptococci
Spirilla - Rigid spiral-shaped bacteria
Filamentous - Thread-like, cells elongate but don’t divide

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Bacteria, Archaea, Protozoa, Algae, Fungi, Viruses, Multicellular animal parasites (helminths)

The Prokaryotes - Bacteria
Unicellular. May possess a flagella for movement. Aerobic (live in O2). anaerobic (can’t live in O2). Facultative (An)aerobe (lives in either environment)

Gram + or Gram - (depends on peptidoglycan in cell wall)
Archaea
Unicellular. Live in extreme environments. Thermophiles (extreme hot temps). halophiles (salty environment). Methanogens (methane-producing). Psychrophiles (extreme cold)

The Eukaryotes - Protozoa
Aerobic eukaryotes. Cellulose in cell wall. Many ways of locomotion (movement). Cilia (hair-like). Flagellates (whip-like). pseudopodia (fake feet)
Algae - Unicellular or multicellular. Cyanobacteria or blue-green algae. Photosynthetic. Live in damp soil, water, and on rocks
Fungi - Mushroom, molds, yeast. Cell wall contains chitin. Reproduce by releasing spores. Decomposers
Viruses - non-living, non-cellular entities. Consist of:

DNA or RNA (nucleic acid)

Surrounded by a protein coat
Require a host to reproduce

Helminths
Not technically microorganisms, but part of their life cycle is microscopic. Flatworms. Lung Fluke Disease (Paragonimiasis). Roundworms. Ascariasis (infection of small intestine). Their parasitic tendencies are important for clinical reference

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Cells are the simplest form of life

Cell Theory
1. All living organisms are composed of cells. They may be unicellular or multicellular
2. The cell is the basic unit of life
3.  Cells arise from pre-existing cells

Prokaryotes vs. Eukaryotes
Prokaryotes - Simple, no nucleus or membrane-bound organelles. Bacteria and Archaebacteria. Grow and reproduce commonly through asexual reproduction - binary fission. Typically rod, spherical, or corkscrew shape
Eukaryotes - Complex, membrane-bound organelles. Protists, plants, fungi, animals. Grow and reproduce via mitosis or meiosis
Autotroph
Carbon is obtained directly from CO2. Photoautotroph - Light. Chemoautotroph - inorganic oxidation (of water, minerals, nitrogen gas)
Heterotroph
Carbon is obtained from other things (not directly CO2). Photoheterotroph - Energy from light. Chemoheterotroph - depend on organisms for carbon
Prokaryotes - Reproduction
Genetic Transfer/Bacterial conjugation

Prokaryotes can grab stray DNA from the environment

Plasmid transfer***

This is how prokaryotes get variation!

Antibiotic resistance, new virulence factors, diversity

Binary Fission

Rapid reproduction of 2 identical daughter cells

Eukaryotes - Reproduction
Mitosis

Somatic/Body cells

Meiosis

Gametes

Egg/Sperm

Variations & Diversity come from mutations