Aerotaxis

V. Alexiades - UTK Bacterial Aerotaxis
Collaborators: Mustafa Elmas (UTK), Gladys Alexander (UTK BCMB). 2015-2019

Chemotaxis is the ability of motile bacteria to navigate gradients of chemical substances. Aerotaxis is the ability to navigate oxygen gradients.
The motile soil bacterium Azospirillum brasilense colonizes the rhizosphere and promotes the growth of various plants. It is able to detect narrow regions in a gradient where the oxygen concentration is low enough to support its microaerobic lifestyle and metabolism.

We developed a mathematical model for aerotaxis band formation that captures critical features of aerotaxis in A. brasilense. The model recapitulates experimental observations of the formation of a stable aerotactic band within 2 minutes of exposure to the air gradient that were not captured in previous modeling efforts.

Using experimentally determined parameters, the mathematical model reproduces the location and width of aerotactic band that matched the experimental observations.
This validated model also allowed us to capture the range of oxygen concentrations the bacteria prefer during aerotaxis, and to estimate the effect of parameter values (e.g. oxygen consumption rate), which are difficult to obtain experimentally.

V Alexiades, M Elmas, G Alexandre, "Band formation in bacterial aerotaxis", Neural, Parallel, and Scientific Computations 25: 307-312, 2017.

M Elmas, V Alexiades, L O'Neal, G Alexandre, "Modeling Aerotaxis Band Formation in Azospirillum brasilense", BMC Microbiology 19:101, 2019.

Work on pathways and signaling:

M Elmas, T Mukherjee, V Alexiades, G Alexandre, "A two pathways model for chemotactic signaling in Azospirillum Brasilense", Neural, Parallel, and Scientific Computations 25: 345-357, 2017.

T Mukherjee, M Elmas, L Vo, V Alexiades, T Hong, G Alexandre, "Multiple CheY homologs control swimming reversals and transient pauses in Azospirillum brasilense",
Biophysical J. 116(8):1527-1537, 2019.