[BIO 120.11] Module 3 Part 2: Culturing Bacteria - Incubation Conditions

Temperature, Molecular oxygen

What are 2 factors that are considered for incubation conditions?

Minimum Cardinal Temperature

Cardinal Temperature: Membrane gelling

Minimum Cardinal Temperature

Cardinal Temperature: Transport processes so slow that growth cannot occur

Optimum Cardinal Temperature

Cardinal Temperature: Enzymatic reactions occurring at maximal possible rate

Maximum Cardinal Temperature

Cardinal Temperature: Protein denaturation

Maximum Cardinal Temperature

Cardinal Temperature: Collapse of the cytoplasmic membrane occurs

Maximum Cardinal Temperature

Cardinal Temperature: Thermal lysis

Psychrophile, Polaromonas vacuolata

Microorganism category and example that grow optimally at 4 degrees Celsius

4 deg C

What is the optimal temperature for psychrophiles?

Mesophile, E. coli

Microorganism category and example that grow optimally at 39 degrees Celsius

39 deg C

What is the optimal temperature for mesophiles?

Thermophile, Geobacillus stearothermophilus

Microorganism category and example that grow optimally at 60 degrees Celsius

Hyperthermophile, Thermococcus celer, Pyrolobus fumarii

Microorganism category and example that grow optimally at 88 and 106 degrees Celsius, respectively

60 deg C

What is the optimal temperature for thermophiles?

88 deg C

What is the optimal temperature for hyperthermophiles (below boiling temperature)?

106 deg C

What is the optimal temperature for hyperthermophiles (above boiling temperature)?

Mesophile

Psychrotolerant and thermotolerant bacteria can still fall under what category of bacteria based on temperature requirement?

TRUE

T/F: Molecular oxygen (O₂) is an essential nutrient for many microbes, but can also be lethal to some microbes

FALSE

T/F: Molecular oxygen (O₂) is an essential nutrient for all microbes

TRUE

T/F: All microorganisms convert O2 to toxic oxygen byproducts during respiration or by cellular electron carriers

FALSE

T/F: Only some microorganisms convert O2 to toxic oxygen byproducts during respiration or by cellular electron carriers

Respiration, Cellular electron carriers, Flavoproteins

Fill in the blank: All microorganisms convert O₂ to toxic oxygen byproducts during ___ or by ___ (e.g. ____)

TRUE

T/F: Oxygen is toxic to all microorganisms

FALSE

T/F: Oxygen is only toxic to some microorganisms

Superoxide anion (O2-), Hydroxyl radical (OH), Hydrogen peroxide (H2O2)

What are 3 examples of toxic oxygen byproducts? SHH

Macromolecules

What do superoxide anions (O2-) oxidize?

Superoxide anion (O2-), Hydroxyl radical (OH)

What oxygen byproducts can oxidize macromolecule?

Macromolecules

What do hydroxyl radicals (OH) oxidize?

Damages cell components

What does hydrogen peroxide do as an oxygen by-product?

TRUE

T/F: H₂O₂ is less toxic than O₂- and OH

FALSE

T/F: H₂O₂ is more toxic than O₂- and OH

Catalase

What enzyme can be used to detoxify 2 hydrogen peroxides?

Catalase

What enzyme is responsible for the reaction shown in the image?

Peroxidase

If you have a hydrogen peroxide and NADH, what enzyme can be used to detoxify the hydrogen peroxide?

Superoxide dismutase

What enzyme can be used to detoxify two superoxide anions to produce hydrogen peroxide?

Superoxide dismutase / catalase in combination

What enzyme can be used to detoxify superoxide anion to water and oxygen molecules?

Superoxide reductase

What enzyme can be used to detoxify superoxide anion to hydrogen peroxide and oxidized rubredoxin?

Peroxidase

What enzyme is responsible for the reaction shown in the image?

Superoxide dismutase

What enzyme is responsible for the reaction shown in the image?

Superoxide dismutase / catalase in combination

What enzyme is responsible for the reaction shown in the image?

Superoxide reductase

What enzyme is responsible for the reaction shown in the image?

Obligate aerobe, Micrococcus luteus

Microorganism Type and Example: Thrives in the presence of atmospheric oxygen, will not grow without oxygen

(+) SOD, (+) Catalase

Enzyme content of obligate aerobes

(+) SOD, (+) Catalase

Enzyme content of facultative anaerobes

Facultative anaerobe, E. coli

Microorganism Type and Example: Does not require oxygen, but it is advantageous or it promotes their growth

Aerotolerant Anaerobe, Streptococcus mutans

Microorganism Type and Example: Not affected by oxygen, but usually in experiments, they are provided with oxygen (less complicated)

(+) SOD, (-) Catalase

Enzymes for Aerotolerant anaerobes

(-) SOD, (-) Catalase

Enzymes for strict anaerobes

Strict anaerobe, Methanobacterium formicicum

Microorganism Type and Example: Thrives without oxygen, it is lethal for them

(+) SOD, (±) Catalase at low levels

What is the enzyme content for microaerophiles?

Microaerophile, Spirillum volutans

Microorganism Type and Example: They need oxygen, but the concentration should be below atmospheric level

Hydrogen peroxide, oxidoreductase, superoxide anion

Catalase disproportionates ___, and SOD is an ___ that serves to dismutate the ___.

Use Shaker Incubator

What can I do in a laboratory if I need to grow bacteria in a broth?

Sparging System

Aside from shaker flasks, what is another equipment used to promote aeration? Usually used in bioreactors

Nitrogen gas

What gas can be used to remove or displace oxygen from a system?

Microaerophilic Jar or can (Candle inside jar)

What can be used to cultivate microaerophiles?

Anoxic Jar, Anoxic Glove Bag

What can be used to cultivate anaerobes?

Kitchen jars with oxygen absorbers

What can be used as an alternative for anoxic jars?