Abstract 96
Board 18
- How to measure out of plane
colony growth?
- How to model these
growth dynamics?
Vertical growth dynamics of microbial communities
Pablo Bravo, Siu Lung Ng, Brian Hammer, Peter Yunker
0
24
\( 160 \mu m\)
0
1000
Height (\(nm\))
Growth time (\(h\))
Interferometry imaging of microbial communities
Light intensity of the measurement
2D Topography
1D Profiles
Vertical growth timelapse
Qualitative behavior and some key insights
- (A) and (B) show the representative dynamics, with two regimes separated by a characteristic length scale L
- (C) and (D) show that nutrient depletion is not the limiting factor for vertical growth.
- (E) Diffusion of a limiting nutrient recovers the two regime dynamics
Interface model, the
extra-simplified version
\frac{dh}{dt} = \alpha\cdot\text{min}(h, L)-\beta\cdot h
- Available region that can grow, due to diffusion inside the colony, is approximated as \( \text{min}(h,L)\).
- No explicit nutrient dependency since it is not the limiting factor.
- Recovers the two regimes, and is simple enough that you may actually use it!
Colony height
Growth rate
Limiting length
Decay rate
Model predicts steady-state heights accurately
- Additional measurements were performed on new colonies, measured every 2 days, for a 2 week period.
- 48 hours of data may not be enough to narrow down all the parameters
- RMSE between the fits barely changes in the 48h period, hinting that while the model is correct, prediction may be
below the real values
48h only fit
Interface model
describes growth of
varied microbes
- Gram positivity-negativity, different shapes and sizes are OK!
- EPS production does not change dynamics either
- And neither does being aerobic or anaerobic!
All the details, data, derivations, and many more figures soon with the preprint!
Pablo Bravo
pbravo7@gatech.edu
