1. The Dependence of Bacterial Growth Rate on Osmotic Pressure
Rico Rojas

2. “Ever since I was a child I have had this instinctive urge for expansion and growth,” - Bruce Lee

3. Goal: To measure and understand if and how bacterial cell growth depends on osmotic pressure.
Vibrio

4. Terminology
Elastic Strain
Growth Rate (Strain Rate)

5. Raw Data: length vs. time
T=30 s

6. Strain rate vs. time
n=32 v

7. Turgor pressure modulates growth rate
T=30 s
v(s-1)

8. If the oscillations are purely elastic:
The growth rate during the periods of high osmolarity should be the same as that during low osmolarity. In addition, the growth rate averaged over the periods during which the media is switching should be equal to this value.
Amplitude of oscillation in length should not depend on the driving frequency.

9. Tracking WGA-stained E. coli

10. Cell width

11. Cell width 2

12. Cell length

13. Cell growth rate, average with all traces. Extracted average.

14. Is growth rate different?
Segmented concentration profile. Segmented growth rate with trace of av
velocity during constant conc.
Also show the non-shock curve

15. Extracted av growth rate during const. conc. Average waveform.

16. Scaling of Growth Rate vs. Period (100 mM)

17. Scaling of Growth Rate vs. Period (200 and 100mM)

18. What about the amplitudes
Segmented Length (also small segmented conc. profile again).
Definition of the 2 amplitudes.

19. Scaling of the amplitudes, 100 and 200 mM

20. To do