I Microbial growth
A.Growth of bacterial cultures
B. Influence of nutrients
C. Growth curve
D. Measurement of growth
E. What affects microbial growth?
Nutrient availability
Physical environment
Temperature
pH
Water
O2
 
Cold Loving” psychrophiles
Food spoilage-psychrotrophs
Glaciers
Microbes in ice
Ice core
Organisms from core
Active(?) microbes in ice
Ice aggregates Mixture of organisms
 
Chlamydomonas nivalis - pink snow
Most Pathogens-Mesophiles
Bacillus cereus
Most pathogens are mesophiles
Thermoplasma Thermophile
Archaea
Thermoacidophile
No cell walls
Evolution to eukaryotes?
Molecular data says NO!
But lack of cell wall allows
   it to “borrow” genes
Thermus aquaticus
TAQ polymerase
PCR Enzyme
Hot spring organisms
Pyrolobus fumarii Hyperthermophile
Extreme early earth conditions?
Influence of pH on microorganisms
Fungus colonizing acidic fruit
Influence of pH on different enzymes
Mining and acid mine drainage
pH approaching zero!
Acidic bog
Helicobacter pylori
Ulcer awareness week! October 6-13th
Alkaline lakes
Lake Magadi in Kenya
Alkaline Salts
Rain + evaporation dissolves salts
binding with hydrogen ions
Soap Lake in Washington

Halomonas campisalis pH 9.5 salt concentration of 12.5%

Healing  mineral waters?
Enzymes from alkalophiles
Fish
Strawberries
Tomatoes
Dry foods and environments
Animal cell Plant cell
Osmotic Pressure
Isotonic
 
 
 
Hypotonic
 
 
 
Hypertonic
Plasmolysis
Water leaves cell
Membrane shrinks
DNA disordered
Metabolism disrupted
Salted fish
Staphylococcus aureus on skin
Ocean - salt water
Dead Sea
Solar Evaporation
Ponds
Salt production
Heat production
Halobacterium
How would these
cells fare is
distilled water?