BIO240 Module 6A Cultivating Microorganisms

Naming formula for metabolic categories

Energy source + electron source + carbon source + troph

Energy sources

Chemo - chemical

Photo - light

Electron Sources

Organo → Organic

Litho → Inorganic

Carbon Sources

Hetero → Organic (c-c bonds)

Auto → Inorganic (CO2, bicarbonate)

Aerobic Growth

Obligate → require O2

Microaerophiles → grows best in low levels of O2

Anaerobic Growth

Aerotolerant → Not hared by O2 doesn’t use it

Obligate → cannot grow with O2 present

Facultative → Can grow without O2 but grow better with

Toxic Oxygen Species

Responsible for harmful effects of oxygen

• Pigments, enzymes (e.g., superoxide dismutase, catalase, peroxidase), and antioxidants used for protection

Mesophiles

Love intermediate temperatures

Psychrophiles

Cold-loving organisms

Psychrotolerant

Microorganisms that can survive at low tempatures

Saturation impact on membrane fluidity

Unsaturated → maintain high fluidity across membrane (psychrophile)

Saturated → reduces membrane fluidity (theromilepholes)

How do thermo/hyperthermophiles sustain life and grow at high temperatures

Critical amino acid substitutions in key locations

• Fold in heat-tolerant way

Compatible solutes

• promote the stability of proteins

Solid Media

Required for isolation of a pure culture

Liquid Culture

enrich microorganisms in a mixed culture to grow them high densities

Complex Medium

Has undefined components

Defined Medium

Chemical makeup of each ingredient is precisely known

Selective media

Allows isolation of a specific microorganisms as the media inhibits growth of other microorganisms

Differential media

Results in unique visual characteristics that allow differentiation between target microorganisms and others on the plate

Enrichment culture media

Grow a certain type of microorganism and not others

• does not inhibit, just does not provide what others may need to grow

Streak Plate method

Used to isolate individual colonies for future work

Spread plate method

Used to count viable cells; colonies form on surface because cells are spread onto the surface of a solidified agar plate

Pour plate method

Used to count viable cells; cell colonies grow inside agar and on surface because they are added to molten agar before pouring plates; requires organism to be thermotolerant