Lecture 7 (covers video A)
Tuesday, February 16, 2021 11:03 PM
• Aged cells are compared to unaged--same strain, only grown for 1-2d, fresh and metabolically-active-- cells.
Once aged cells show growth advantage, they exhibit the GASP phenotype.
• Hypothesis: is the GASP phenotype present? Does it differ in different media?
• Pipetting expt: determining how many colony-forming units (CFUs) will come up if a mL of culture is diluted from
0,3,6,9 days? CFU is a measurement of concentration.
○ Each spot represents a 10-fold dilution.
○ In earlier spots, there's so much growth cells are merging onto one another-- must look at spot 5+.
○ Aged cells are grown in their LTSP-- 90% of the cells in the growth culture are dead. Shining light onto a
culture full of dead cells and measuring the OD will not determine how many aged cells are still alive/can
grow.
○ Spot 1 is 10ul of the diluted culture (10ul culture + 90ul LB). This means it contains 1ul of the original
culture. ->
○ Spot 1: CFU/10^-3ml = CFU * 10^3/ml
Tuesday, February 16, 2021 11:03 PM
• Aged cells are compared to unaged--same strain, only grown for 1-2d, fresh and metabolically-active-- cells.
Once aged cells show growth advantage, they exhibit the GASP phenotype.
• Hypothesis: is the GASP phenotype present? Does it differ in different media?
• Pipetting expt: determining how many colony-forming units (CFUs) will come up if a mL of culture is diluted from
0,3,6,9 days? CFU is a measurement of concentration.
○ Each spot represents a 10-fold dilution.
○ In earlier spots, there's so much growth cells are merging onto one another-- must look at spot 5+.
○ Aged cells are grown in their LTSP-- 90% of the cells in the growth culture are dead. Shining light onto a
culture full of dead cells and measuring the OD will not determine how many aged cells are still alive/can
grow.
○ Spot 1 is 10ul of the diluted culture (10ul culture + 90ul LB). This means it contains 1ul of the original
culture. ->
○ Spot 1: CFU/10^-3ml = CFU * 10^3/ml
